Human asthma and rhinitis involve the excessive secretions of mucus. Cultured human airways incorporate radiolabeled molecules into newly synthesized mucus permitting monitoring of mucous secretion. Human lung mucus has been characterized biochemically and the immunological as well as neuropharmacologic control of mucous secretion defined. The site and control of human lung parenchyma of mucous secretion defined. The site and control of human lung parenchyma versus airway prostaglandin production has been identified and the factors generated by anaphylaxis causing prostaglandin synthesis isolated. The histologic responses to rat mast cell granules have been characterized both in rat and monkey skin and the factors responsible for eliciting the inflammation isolated and characterized. The effects of steroids on late phase allergic reactions has been examined. The relationship between calcium influx and rat mast cell degranulation has been analyzed as have the responses of mast cells to histamine stimulation. The autonomic and autocoid responsiveness of subjects with asthma, allergic rhinitis and cystic fibrosis has been studied. An assay for urinary histamine has been developed and the normal range of histamine established.